Might be, yes. It is a trade of size of depacker, packrate, speed of depacking. As there are no shifts speed is good and size as well. If you pack large files, then it might be worth to have 16bit offsets.
Or 12bit counts.
zpack w/o endmark (that is max. 0x40 literal bytes) packs demo0006.o from 15400 downto 9751bytes.
W/ endmark it is 9754 bytes but depack is 6 bytes shorter.
For reference: A tweaked version of lz4 shrinks it down to 9394 bytes. But the packer is much more complicated.

I learned, the idea behind demozoo is to archive demos. But I agree regarding tech test. But I think for game protos it is ok. At least a central point to search them. And if in doubt, one can always ask the webmaster.

Thanks. My very first demo-compo (after 33 years hacking 🙂 , and no, I did not start as baby).
I looked into the sources of the RasPi 128b demo. They do system calls. But I did not yet fully understand the code.
No matter, they have floating point and no need to do a setup.
With 4 bytes they can write 60 bytes at a time. Quiet unfair. Good I did not know it before hand 🙂
BTW: Out call to everyone here: Archive your stuff on demozoo.org! There are only a few Lynx productions and a good part is from BLL.